24: LABORATORY EXERCISES. 



posed of nitrogenous substances.) Place 

 a chemical thermometer in the test-tube 

 and hold the tube in a beaker-glass of 

 cool water. Gradually heat the water, 

 stirring continually with the test-tube. 



a. What change takes place in the egg 



albumen? 



b. At what temperature does this change 



occur? 



2. Boil some milk in a pan. What do you 



notice? Heat several times and see if 

 same result follows. 



3. Cook a small piece of meat. How does the 



heat affect its outer surface? What is 

 your conclusion in regard to the compo- 

 sition of meat? 



B. Smell when burning. 



1. Place a small piece of lean meat on the top 



of a coal fire and allow it to burn. Have 

 you ever noticed this smell before? If 

 so, what caused it? 



2. In the same way test milk, peas, or beans. 



Result? 



C. Effect of nitric acid and ammonia. 



i. Pour a little concentrated nitric acid on a 

 piece of hard-boiled egg in a test-tube. 



a. What do you observe? 



b. Wash off the egg with water, add a 



little concentrated ammonia, and 

 note result. 



2 Put into a test-tube some starch paste made 

 as in 9 above; into a second tube some 



